Since the invention of the telephone, people have had a desire to be able to see the person to whom they were speaking. A prerequisite for that wish was the ability to transmit visual images over distances, and to combine both sending and receiving capabilities into a single device. The advance of video technology has made this possible.
It is now easily achievable to create devices that both transmit and receive audio and visual signals. Two such devices that are currently commercially available are the Lumaphone by Mitsubishi and the Stillvideo Picture Phone by Sony. One problem with the devices currently available is that they do not allow full motion video. The devices operate by digitizing a video signal, transmitting that image to a receiving modem, then reconstructing the video image. The transmission time for that process is approximately 6-8 seconds. Thus, the image transmitted is basically a series of "still photos" of relatively poor quality. Further, since the devices are not equipped as speakerphones, the image transmitted will always show the speaker with a handset.
Another disadvantage inherent in the currently available devices is that such devices are relatively large and cumbersome. This reduces the usefulness of such a device in the consumer market.
Another problem with the currently available products is that voice communication is blocked while the video image is being transmitted. While it is desirable to be able to see the person you are conversing with, it is imperative that you be able to speak to him unimpeded by video transmission. The currently available devices block voice transmission for 6-8 seconds each time an image is transmitted.